Dental Ring Light

Archived from groups: rec.photo.digital (More info?)

On Wed, 26 Jan 2005 19:34:03 -0600, "Gene F. Rhodes" <"gfrhodes"@ cox.net>
wrote:
>I'm having trouble finding quality high intensity LEDs.
>My first batch projects a yellow ring with green tint in the middle.
>Is there such a thing as a true white high intensity LED ?
>
>Gene http://www.photoprojects.net/

Gene,
Ya might do well you ask the guys in this newsgroup:
alt.binaries.schematics.electronic

They do all kinds of neat stuff with LEDs.

Archived from groups: rec.photo.digital (More info?)

On Wed, 26 Jan 2005 19:34:03 -0600, "Gene F. Rhodes" <"gfrhodes"@
cox.net> wrote:

>I'm having trouble finding quality high intensity LEDs.
>My first batch projects a yellow ring with green tint in the middle.
>Is there such a thing as a true white high intensity LED ?

Depends what you mean by "true white". If you're asking if a LED can
emit white light the answer is yes... sort of...

White LED's are actually have three separate LED's (red, green and
blue) inside the one LED package. The three LED's produce white by
mixing the output of the three separate LED's in the correct
proportions to produce white.

Archived from groups: rec.photo.digital (More info?)

"Gene F. Rhodes" <"gfrhodes"@ cox.net> writes:

> I'm having trouble finding quality high intensity LEDs.
> My first batch projects a yellow ring with green tint in the middle.
> Is there such a thing as a true white high intensity LED ?
>
> Gene http://www.photoprojects.net/

Well presumably there is, since there are LED ring lights for sale, such as:
http://www.bhphotovideo.com/bnh/co [...] 937&is=REG

--
Michael Meissner
email: mrmnews@the-meissners.org
http://www.the-meissners.org

Archived from groups: rec.photo.digital (More info?)

Very true ... the "white" is actually a relatively strong bluish color. I
would ask to see a spectral plot of the LED's output before trying to use
it for photography.

First:
I have been somewhat disappointed with the so-called "white LEDs" so far
.... even in flashlight-type applications.

Second:
I would love to try a three-LED light source ... one with Red-Blue-Green
LEDs. Who makes one?








"Dave Martindale" <davem@cs.ubc.ca> wrote in message
news:cti53b$jpo$2@mughi.cs.ubc.ca...
> NOsecSPAM@nbnet.nb.ca writes:
>
> >Depends what you mean by "true white". If you're asking if a LED can
> >emit white light the answer is yes... sort of...
>
> >White LED's are actually have three separate LED's (red, green and
> >blue) inside the one LED package. The three LED's produce white by
> >mixing the output of the three separate LED's in the correct
> >proportions to produce white.
>
> Actually, most "white" LEDs are actually blue-emitting LEDs with a
> phosphor coating. The phosphor absorbs some of the blue and emits
> yellow-green instead. So you get whitish light, but the colour often
> changes with angle off axis, and colour rendition isn't that good.
>
> A real 3-chip LED would be better, but more expensive.
>
> Dave

Archived from groups: rec.photo.digital (More info?)

http://www.superbrightleds.com/
have good quality LEDs compared to some others.
Gene http://www.photoprojects.net/dental.html



Steve Wolfe wrote:

> > First:
> > I have been somewhat disappointed with the so-called "white LEDs" so far
> > ... even in flashlight-type applications.
> >
> > Second:
> > I would love to try a three-LED light source ... one with Red-Blue-Green
> > LEDs. Who makes one?
>
> A quick perusal of Digikey's catalog turned up options from Lumex and
> Panasonic, ranging from $2.30 to over $11.00 each in low quantities. I only
> skimmed through very quickly, I imagine that there will be options from
> other manufacturers as well.
>
> steve